The U.S. Food and Drug Administration has cleared Elon Musk’s company Neuralink to implant a second brain chip in another human test subject, the Wall Street Journal reported Monday. Neuralink is seeking to fix a problem that arose in its first subject, Noland Arbaugh, a quadriplegic who remains unable to move his extremities below his shoulders. Namely, several small wires connected to the brain-implanted device had come out of position, causing the device to work less well in translating his thoughts into computer cursor movements. “I was on such a high and then to be brought down that low. It was very, very hard,” Arbaugh said in an interview with the WSJ. “I cried.” Neuralink hopes to solve the issue by implanting the wires deeper into the subject’s brain, according to a document viewed by reporters. The company hopes to perform the procedure in June—and also wants to implant 10 more subjects by the end of 2024.